Setting the default values to "opt in" on some funky toolbar duing a simple update procedure is an evil thing**. The only reason you keep this up is because you hope I will just once forget to uncheck this box and then I'lll be stuck with another useless toolbar on my browser. You know what? if it was the best thing since sliced bread, I'd already have it. If you were honest, you would set the default to off and maybe include some blurb about how great it was and I should check in on because my life would be changed forever for the better... No, I didn't think so. Anyway, here's the deal. Next time I see an update and it includes yet another thing to add on to my computer and the default value will result in said bit of trash being added to my computer, I will turn off updates alogether.
*This is known as a dark programing practice, Similar to how insurance companies get people to pay for flight insurance, or how LA Fitness will let you join with a single click, but you will need to wade through pages of crud and wait two weeks to get out.
Instead of turning off updates all together, I'd like to encourage you to enable automatic updates instead. While not completely silent, it does allow your flash installation to stay as secure as possible with minimal amount of noise. For the quarterly updates that do pop up UI, you can simply ignore them. After 30 days we'll update silently in the background. Here's a faq that describes the process.
ps. I hear you regarding your opt-out concerns and will pass these along to the team that is in charge of this page.